Exam 7: Continuous Probability Distributions

The average score of 100 students taking a statistics final was 70 with a standard deviation of 7.Assuming a normal distribution,what test score separates the top 25% of the students from the lower 75% of students?

The uniform probability distribution's standard deviation is proportional to the distribution's range.

The number of different normal distributions is unlimited.

In a standard normal distribution,µ = ______ and $\sigma$ = ______.

The seasonal output of a new experimental strain of pepper plants was carefully weighed.The mean weight per plant is 15.0 pounds,and the standard deviation of the normally distributed weights is 1.75 pounds.Of the 200 plants in the experiment,how many produced peppers weighing between 13 and 16 pounds?

A z-score is the distance between a selected value (X)and the population mean (µ)divided by the population standard deviation ( $\sigma$ ).

What is the proportion of the total area under the normal curve within plus and minus two standard deviations of the mean?

A cola-dispensing machine is set to dispense a mean of 2.02 liters into a container labeled 2 liters.Actual quantities dispensed vary and the amounts are normally distributed with a standard deviation of 0.015 liters.What is the probability a container will have less than 2 liters?

Which student scored better compared to the rest of the section? _______________

Non-stop Airlines determined that the mean number of passengers per flight is 152 with a standard deviation of ten passengers.Practically all flights have between 142 and 162 passengers.

The annual commissions per salesperson employed by a manufacturer of light machinery averaged $40,000 with a standard deviation of $5,000.What percent of the sales persons earn between $32,000 and $42,000?

Two normal distributions are compared.One has a mean of 10 and a standard deviation of 10.The second normal distribution has a mean of 10 and a standard deviation of 2.Which of the following is true?

The standard normal probability distribution is unique because it has:

The distribution of the annual incomes of a group of middle management employees approximated a normal distribution with a mean of $37,200 and a standard deviation of $800.About 68 percent of the incomes lie between what two incomes?

For the normal distribution,the mean plus and minus 1.96 standard deviations will include about what percent of the observations?

The mean of a normal distribution is represented by $\sigma$ .

The uniform probability distribution is symmetric about the mode.

When referring to the normal probability distribution,there is not just one;there is a "family" of distributions.

The average score of 100 students taking a statistics final was 70 with a standard deviation of 7.Assuming a normal distribution,what is the probability that a student scored 90 or higher?

The standard normal distribution is a special normal distribution with a mean of 0 and a standard deviation of 1.